From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: ARC-Seal: i=1; a=rsa-sha256; t=1517131757; cv=none; d=google.com; s=arc-20160816; b=g5eRgLqbIWCazxL1NU2wKlweWnvsMPXm8wEW4iVJvqf+nksyDz0MmRQGI1KTKRLKBH 7GEnNNLCdzglOYIkLLIdTLrQbI5OiktNLfUol9NUYM5QPd7m3HFZZop/eMYrptfIhVQz vZCpC5hzgMEHvUDR6Y5trSeWP67L8Nz+PAZLOmci2eaIswIrAboLgnx2RDR0DfNzmT4L O0OKDP4DnCpy6Q8mzXN3lMmTGWpVXPmtqL6ZnKQfx/Shv/o7R9a0qP2zu03lcegnL3UC TwwDzhqCb8fHzoR4Sl8gwXHUSqKoOVG1NHyG/ElYEafyVxCWaI0Kbr8rQKhGdwoU+sOl 3aBg== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=user-agent:in-reply-to:content-disposition:mime-version:references :message-id:subject:cc:to:from:date:sender:dkim-signature :arc-authentication-results; bh=3RMQYdOqeR3+eO75afvnmf/H8X8JJd6uw181SeG4uz4=; b=iKOGEch8tmbW+hGYDolzTTdqmfaZ35+0B/Mt5E64+WnaWTz4CxmPswRUAESYlWVSVf S2MRp4RDBKWIxOMOsFJXoBkLWpw+uhC/Mb+NhFh6CCRLlBjH15Vh1ZuV1uGWT8G4gi4q B0N1zfzQR4YOpp0luHM9bhtste6+dX0ECzL4wQ/u8sTLiMjMEwwSLWgkIpUa7XlivTKt 198H5sKorN66+Pkx+rvrE6WCS5PlPOH90Qenl2JOU04Glrp/p1qtLAThhIHuMjXIvZBK YYBETqmO+tiO87YtiXale6LgDICbluOKfci3H3DEvIWDiX3QLnxa5nY6K3lnIA2px0ms P1Xg== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@gmail.com header.s=20161025 header.b=oHTpKkcZ; spf=pass (google.com: domain of mingo.kernel.org@gmail.com designates 209.85.220.65 as permitted sender) smtp.mailfrom=mingo.kernel.org@gmail.com Authentication-Results: mx.google.com; dkim=pass header.i=@gmail.com header.s=20161025 header.b=oHTpKkcZ; spf=pass (google.com: domain of mingo.kernel.org@gmail.com designates 209.85.220.65 as permitted sender) smtp.mailfrom=mingo.kernel.org@gmail.com X-Google-Smtp-Source: AH8x224SdN3TjW3u82RtnkvzKtn6zwbaRLPMmYaaQXZR1jswFfZsT0/bnnNLak/oqicGxCLB5yTSdA== Sender: Ingo Molnar Date: Sun, 28 Jan 2018 10:29:14 +0100 From: Ingo Molnar To: Dan Williams Cc: tglx@linutronix.de, linux-arch@vger.kernel.org, kernel-hardening@lists.openwall.com, gregkh@linuxfoundation.org, x86@kernel.org, Ingo Molnar , Andy Lutomirski , "H. Peter Anvin" , torvalds@linux-foundation.org, alan@linux.intel.com, linux-kernel@vger.kernel.org Subject: Re: [PATCH v5 07/12] x86: remove the syscall_64 fast-path Message-ID: <20180128092914.dabnzq7arv4bebhn@gmail.com> References: <151703971300.26578.1185595719337719486.stgit@dwillia2-desk3.amr.corp.intel.com> <151703975137.26578.11230688940391207602.stgit@dwillia2-desk3.amr.corp.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <151703975137.26578.11230688940391207602.stgit@dwillia2-desk3.amr.corp.intel.com> User-Agent: NeoMutt/20170609 (1.8.3) X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-THRID: =?utf-8?q?1590732047884904390?= X-GMAIL-MSGID: =?utf-8?q?1590827949608302551?= X-Mailing-List: linux-kernel@vger.kernel.org List-ID: * Dan Williams wrote: > Quoting Linus: > > "Honestly, I'd rather get rid of the fast-path entirely. Compared to > all the PTI mess, it's not even noticeable. > > And if we ever get CPU's that have this all fixed, we can re-visit > introducing the fastpath. But this is all very messy and it doesn't > seem worth it right now. > > If we get rid of the fastpath, we can lay out the slow path slightly > better, and get rid of some of those jump-overs. And we'd get rid of > the ptregs hooks entirely. > > So we can try to make the "slow" path better while at it, but I > really don't think it matters much now in the post-PTI era. Sadly." Please fix the title to have the proper prefix and to reference the function that is actually modified by the patch, i.e. something like: s/ x86: remove the syscall_64 fast-path / x86/entry/64: Remove the entry_SYSCALL_64() fast-path With the title fixed: Reviewed-by: Ingo Molnar Thanks, Ingo